R1800 refillable cartridges

So I'm getting ready to jump into the non-OEM ink arena, but am a little confused by the different refillable cartridges available. Inkjetcarts says theirs are the most up-to-date, need vacuum filling. Inkjetfly says theirs are the most up-to-date, don't need vacuum filling (and cost significantly more). Anyone with experience that can help me out here?